This disclosure relates to articles that have metal-containing layers that oxidize.
Gas turbine engine components are typically subjected to relatively high operating temperatures. To protect from the high temperature, the component can include a protective thermal barrier layer system. Typically, the layer system includes a ceramic layer and a bond layer between the ceramic layer and the component to facilitate adherence of the ceramic layer. The bond layer typically includes aluminum that oxidizes to form alumina. At least a portion of the alumina forms during use of the component. During use, the component is subjected to a range of temperatures that can cause formation of different phases of alumina.